Electric switching device



Nov. 30, 1954 R. FILLIETTE ELECTRIC SWITCHING DEVICE 3 Sheets-Sheet lFiled June 17. 19,52

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ELECTRIC SWITCHING DEVICE Filed June 17. 1952 3 Sheets-Sheet 2 Nov. 30,1954 Filed June 1'?. 1952 R. FILLIETTE ELECTRIC SWITCHING DEVICE 3Sheets-Sheet 3 United States Patent ELECTRIC SWITCHING DEVICE RaymondFilliette, Rueil-Malmaison, France, assignor `to :La TlmcaniqueElectrique (Socit Anonyme), Seine, France, a French company paratus,such as contactors'and circuit breakers, for example for the control ofhoists and lifts, controllers for y.the .control of auxiliary circuitsand all -such apparatus having a large number of contacts.

According to the invention an `electric switching device comprisesalever connected to a current lead-in terminal, which lever is adapted tomove between two opposed fixed contacts, and is freely mounted upon andmaintained by spring pressure against a fixed bearingmember forming apivot, and against one of the twoaforesaid contacts,.the pivotedmovement of the lever necessary for changing over from one contact tothe other being effected by. mea-ns of a thrust member or other knownexternally operated -rnechanical device, a blade or other free elementbeing .interposed betweenthe said thrust member and the said Jever and-maintained by spring pressurey against the said .leverat a'point closeto the support or pivot of the said lever.

In one 4embodiment of the invention, the spring pressure by which thelever is maintained against its pivot :and the spring pressure by whichthe blade is maintained against the lever are effected by a singlespring acting on thesaid blade, the latter bearing againstfthe lever atat .least two pointssituated on either'side of the said pivot.

' The relative position of the different bearing, pivoting vand contactpoints is determined in such manner lthat the contact pressure of thelever upon eitherfof the freed con- `.tacts is substantially the same.

' The blade freely mounted and maintained against the `lever by springpressure imparts to the latter a certain independence with respect tothe thrust member.

In particular, when the lever abuts against the fixed off-normal contactunder the action of the thrust member the move- 4ment of the thrustmember can continue without causing any shock to or deformation of, theelectrical conducting -parts ofthe device. The provision or the bladeforming a transmission member between the thrust member andthe leverpermits a certain amount of lost motion.

'The tension of the spring by which theblade is applied against thelever maybe adjustable, for example by means of a nut forming anabutment at one end of the said spring. This permits of adjusting'thecontactpressure while at the same time maintaining the lever firmlyapplied against its support. This pressure once adjusted, issubstantially unsusceptible to appreciable variations, even after a verylarge number of operations. Nevertheless, if necessary, such variationsas may occur may be readily compensated by adjusting the regulatingscrew. The switching device according to the invention thus affords anappreciable advantage over switching devices comprising a flexible bladewhich is submitted to successive deformations which are likely to modifyits mechanical characteristics and consequently the contact pressure.

IThe Vbearing member on which the lever pivots is directly connected tothe current lead-in terminal. The lever is thus permanently connected tothe said terminal .through a good contact which is ysubjected topractically only negligible friction, whereby a long useful life of the*t* .device isensured. In addition owing to the fact that the lever isapplied against the member by springfpressure, yany play isautomatically taken up.

The various parts of the switching device are mounted inaccordance withthe invention, on a base of insulating material which is ofrectanglllarv shape. and of reduced -mounted on the base 1. The saiddepth, this being possible owing to the very limited width t largenumber of such devices in a limited space, so that electrical controlarrangements of limited dimensions can be provided.

Finally, since the various parts are subjected to limited corcesandpractically negligible friction, they may be nade of material requiringno especial mechanical propertes.

The present invention also includes electric control apparatuscomprising switching devices of the type hereinbefore described.

In the accompanying drawing there is shown by way of ynon-limitativeexample, one embodiment of the invention as applied-to a unipolarreversing switch unit. In the drawing:

Figs. l, 2 and 3 are vertical sections through the unipolar reversingswitch unit, showing the three operating positions thereof, and

Fig.-4 is a front elevation showing a plurality of switch unitslarranged in juxtaposition.

Figs. 5 and 6show diagrammatically two modifications of the switch unit.

The switch units illustrated in the drawing comprise a-base 1ofinsulating. material, preferably moulded, which Ais normally supportedby a steel bar 2 on which it is secured by means of a strap 3 and nutsand bolts 4.

A :rod 5 provided with a current lead-n terminal 5a andhaving securedthereto a bearing member 6 provided with a knife edge, and tworods 13and 15 provided with current leadfout terminals 13a and 15a and providedwith studs :12and 11 respectively, forming fixed contacts are studs andthe bearing member are preferably of silver. The rod 15 is connected toa-bent over arm 14 which is so arranged that the studs 11 and 12 lieopposed one to the other.

The movable contact of the switch comprises a lever 8 having lat oneend,` on its opposite faces and at the level of the-studs 11 and 12 twocontactmembers 9 and 10. The said lever is also provided with a raisedportion 7 intended lto cofoperate with the bearing member 6 and, on theface opposite the said portion two studs 8a and 8b situated von eitherside ofthe portion 7, the stud 8a being positioned yadjacent'thereto.The portion 7 and the contact members 9 and v10 are preferably made ofsilver, while the studs .8a and 8b may consist of treated or casehardened steel.

The lever 8 is maintained against the bearing member 6 Aby a bladev 16pressed against the studs 8a and 8b by stituting the axis oftheextension 5b, while they are free to movey angularly with respectthereto.

Thetline B, parallel to the axis A and passing through the bearing.6,-isV positioned at a distance from the axis A,vwhile thelines C and Dextending through the points at which the bladeV 16 is applied againstthe lever 8 are pocslitioned respectively on either side of the axes Aan B.

The. switch V.is-adapted to be mechanically actuated, for example in thecase of a contacter, by an adjustable thrust member 19 mounted on an arm2i) fixed on a shaft 2Il.by means of a strap 22 and screws 23. Thethrust member 19is. adapted to act on the blade 16 in a directionindicated bythe line E, which is relatively remote from the line Bextending through the bearing 6. It will be understood that the thrustmember could be replaced by a cam, a dog or any other similar mechanicaldevice.

The contact ,membersand the movable members `of the switch are disposedin a groove or recess formed in the face of the base and of sulcientdepth to prevent any substantial lateral movement of the movablepartsand to avoid any accidental contact with the adjacent switch units.

The switch operates in the following manner:

In the inoperative position (Fig. l), the thrust member 19 is free fromengagement with the lever 16 which, under the action of the pressure setup by the sprlng 18 causes the blade 8 to pivot so that the Contactmember 9 engages the stud 11.

Rotation of the shaft 21 through a certain angle causes the thrustmember 19 to act on the lever 16 and the contact member 9 is thuswithdrawnfrom the stud 11 (Fig. 2), thereby breaking the circuitconnected to the terminals 5a and 15a.

Further rotation of the shaft 21 and the correspondlng displacement ofthe blade 16 and lever S, causes the contact member to bear against thestud 12, thereby closing the circuit connected to the terminals 5a and13m Fi 3 rfighe r)elative position of the various lines B, C, D and E issuch that the contact pressure between the contact member 9 and the stud11 (Fig. l) is substantially the same as the contact pressure betweenthe Contact member 10 and the stud 12 (Fig. 3). It is to be noted, inthe latter ligure, that any movement of the thrust member 19 beyond theposition of the lever 8 in which the contact 10 bears against the stud12 causes the blade 16 to pivot on the stud 8a against the action of the0 spring 18. Thus, owing to the flexible manner in which the blade 16 ismounted, the thrust member does not produce any shock which might causedamage to the parts of the switch.

As has hereinbefore been stated, the switch is in the form of a smallunit adapted to be mounted in juxtaposition (see Fig. 4) in a smallspace with other similar units mounted on a common bar 2 Each unit has aseparate mechanical actuating device. These devices may be independentof one another or associated with one another.

The blade 16 may be turned about the rod 5b so as to bring it into theposition shown at 24 (see Fig. 5), the thrust member then beingpositioned at 25 and acting in a direction indicated by the line E. Itwill be understood that the blade 16 as shown in the drawing couldcomprise an extension as indicated at 24a (see Fig. 6), in which casethe blade would extend from the line E to the line E'. In fact, only therelative position of the studs 8a and 8b is important, the form and thedimensions of the blade 16 being purely arbitrary.

In addition, the action of the thrust member may be exerted tangentiallyon the blade 16 instead of being exerted perpendicularly thereto, thisbeing rendered possible due to the sloping form of the said blade. anarrangement would permit of the continuous rotation of the shaft 21, onwhich a number of arms 20 corresponding to an equal number of switchunits may be fixed, the said arms being keyed in well-defined relativeangular positions. In such a case, in order to reduce the friction ofthe thrust member on the blade, the thrust member or the blade may beprovided with a roller. Such an arrangement is particularly advantageousin the case of controllers such as those employed for the operation ofhoists and lifts.

It will be understood that modifications may be made to the switch unithereinbefore described, by substitution of equivalent technical means,without departing from the scope of the present invention. Inparticular, the blade 16 could be replaced by any desired resilientmember secured to the lever 8, for example at the point 8a, the spring18 then bearing directly against the lever, for example at the point 8b.

What I claim is:

1. In an electric switch assembly adapted to connect and disconnect apair of circuit terminals, fulcrum means electrically connected to oneterminal, a rigid electrically conductive lever movable about saidfulcrum between two positions, a contacting point on the lever spacedfrom said fulcrum adapted respectively to engage and disengage the otherterminal in the two positions of the lever, means for applying springpressure to the lever at a pair of spaced points thereof located toeither side of said fulcrum for normally maintaining the lever in oneposition, and means for increasing the pressure Such applied to thelever at that one of said pair of spaced points which is located betweenthe fulcrum and said contacting point over the pressure applied to thelever at the other of said spaced points, in order to bring the lever toits other position.

2. An electric switch assembly as claimed in claim 1, wherein the firstmentioned one of said pair of spaced points is substantially closer tosaid ulcrum than is the other one of the spaced points.

3. An electric switch assembly as claimed in claim 1, wherein the firstmentioned one of said pair of spaced points is located in immediateproximity to said fulcrum, and the other one of said spaced points isspaced a considerably greater distance from the fulcrum.

4. In an electric switch assembly adapted for establishing at least twodifferent conditions of an electric circuit, a stationary support,fulcrum means fixed to said support, a rigid lever movable about thefulcrum between two positions in each of which a respective'one of saidcircuit conditions is established, spring means for applying pressure tothe lever at a pair of spaced points thereof located on either side ofthe fulcrum for normally maintaining the lever in one position, andmechanically actuating means for displacing the lever to its otherposition against the action of said spring means.

5. An electric switch assembly as claimed in claim 4, wherein saidfulcrum is electrically connected to one circuit terminal, and saidlever is electrically conductive and in one of its said positions isadapted to have a contacting point thereof engage another circuitterminal.`

6. An electric switch assembly as claimed in claim 4, wherein saidfulcrum is electrically connected to one circuit terminal, and saidlever is electrically conductive and in one of its said positions isadapted to have a contacting point thereof engage another circuitterminal, and in its other said position is adapted tohave its saidcontacting point disengage said other circuit terminal and have afurther contacting point thereof engage a further circuit terminal.

7. An electric switch assembly as claimed in claim 4, wherein saidfulcrum is electrically connected to one circuit terminal, and saidlever is electrically conductive and in one of its said positions isadapted to have a contacting point thereof engage another circuitterminal, and wherein said mechanically actuating means acts to increasethe pressure applied to the lever at that one of said spaced pointsthereof which is located between said fulcrum and 4said contactingpoint.

8. In an electric switch assembly adapted for selectively establishingat least two different conditions of an electric circuit, fulcrum means,a substantially rigid lever movable about said fulcrum between twopositions in each of which a respective one of said circuit conditionsis established, a pressure-transmitting member engaging said lever atspaced points thereof lying on either side of said fulcrum, a springacting on said member for applying pressure therethrough to both saidspaced points of thelever normally to maintain the lever in one of itssaid positions, and an actuating element for selectively actuating saidmember to bring the lever to its other position.

9. An electric switch assembly as claimed in claim'8, wherein saidspring is adjustable.

l0. In an electric switch assembly adapted for selectively connecting airst circuit terminal to either one of two other terminals, a furcrumelement electrically connected to said lirst terminal, a rigidelectrically-conductive lever movable about said fulcrum between twopositions, adjacent contacting points on opposite faces of the leverspaced from said fulcrum and adapted to make contact with respectivelyrelated ones of said terminals in each of said lever positions, apressure-transmitting member engaging said lever at two spaced pointsthereof on either side of said fulcrum, said member being spaced fromsaid lever intermediate the points of engagement thereof with the leverfor applying pressure therethrough to both said spaced points of thelever to maintain the lever in one of its said positions, said memberhaving anl extension beyond one of said points of engagement thereof,and an actuating element adapted to engage said extension forselectively actuating said member to bring the lever to its otherposition. y

ll. A switch assembly as claimed in claim l0, wherein the relativespacings of said points and said fulcrum are so predetermined that thepressure developed between said contacting points and the relatedterminals in both positions of the lever is substantially the same.

l2. A switch assembly as claimed in claim l0, which comprises a mountingblock of insulating material of narrow elongated generally rectangularform, and means for mounting said fulcrum, said pressure transmittingmember and said spring means adjacent one end of the block and formounting said other terminals adjacent the other end of the block withsaid lever extending therebetween along the length of the block forengagement with said fulcrum and said member and with either selectedone of said other terminals under the action of said spring means.

13. A switch assembly as claimed in claim l0, which comprises a mountingblock of insulating material of narrow elongated generally rectangularform, means for 15 2,517,052

mounting said fulcrum, said pressure transmitting member and said springmeans adjacent one end of the block and for mounting said otherterminals adjacent the other end of the block with said lever extendingtherebetween along the length of the block for engagement with thefulcrum and with said member and with either selected one of said otherterminals under the action of said spring means, and means for mountinga plurality of similar blocks in transversely juxtaposed relationship.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Da te Swinehart Aug. l, 1950

